1. What is a Pump Capacity vs Flow Rate Calculator?

Definition: This calculator determines the pump capacity (flow rate) based on horsepower, pump efficiency, total head, and fluid density.

Purpose: It helps engineers and technicians size pumps and understand the relationship between pump power and flow rate.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Pump capacity (gallons per minute, GPM)
• \( HP \) — Horsepower
• \( \eta \) — Pump efficiency (0-1)
• \( H \) — Total head (feet)
• \( \rho \) — Fluid density (pounds per gallon)

Explanation: The formula relates the mechanical power input (HP) to the hydraulic power output (flow rate against a specific head).

3. Importance of Pump Capacity Calculation

Details: Proper pump sizing ensures efficient system operation, prevents cavitation, and matches system requirements.

4. Using the Calculator

Tips: Enter the pump horsepower, efficiency (default 0.85), total head in feet, and fluid density (default 8.34 lb/gal for water). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the constant 3960 in the formula?
A: This is a conversion factor that relates horsepower, flow rate, head, and specific gravity in consistent units.

Q2: What's a typical pump efficiency value?
A: Centrifugal pumps typically range from 0.6 to 0.9, with 0.85 being a common default value.

Q3: How do I determine total head?
A: Total head is the sum of static head, friction head, and pressure head in the system.

Q4: What density should I use for other fluids?
A: For other fluids, use their specific weight divided by 7.48 (gallons per cubic foot).

Q5: Does this account for system curve effects?
A: No, this calculates theoretical capacity. Actual flow depends on the system curve intersection with the pump curve.